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It's complex , but just give your money to Matt at CNW , and never worry about it again . Hardened new components .
Sprage Clutch
- Thread starter Norton1975
- Start date
Well yes, I have been through 2 or was it 3 of the Chinese Ali express Sprag 18 bearings,both have worked for a brief period then fail to turn the motor over.The first one work for about a thousand kms. The current one I pulled out, having a close look at the inside of the "dog bones" you can see the flats that have worn on the tips of them,so now wonder it did not turn the engine over.And yes I always hold the clutch in whilst starting and have also had a hardened bearing sleeves fitted to both the engine and drive gear to ensure a tight fit and good surface ,But have now given up on that. Currently waiting on a delivery of the MK3 upgrade from Matt at CNW,been a long time coming due to lack of stock from the suppliers. Brett
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Right thing to for all MK 111 owners . You will never regret it . Pricey , yes .
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Found it! Never mind
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The REAL problem is it eventually chatters and can't grab well ( Then failing , breaking up ) at the original inboard and outboard front sprockets . You need hardened ones . CNW . $pend .
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You got lucky my friend . The quality of steel cast of sprockets is so important , no digging in , wear marks or wobbling marks .
There are quite a few lucky people who have used these sprags.
Over the years I've asked if any who have used them have had failures and, up until this thread, the answer was no, all were doing the job.
Now we have one person who has had a problem with them.
I think quite a number of owners tried these sprags after me. I don't know the numbers however.
It is possible that the quality has changed over the years ( deteriorated) as they are made in China, anything goes.
Glen
Over the years I've asked if any who have used them have had failures and, up until this thread, the answer was no, all were doing the job.
Now we have one person who has had a problem with them.
I think quite a number of owners tried these sprags after me. I don't know the numbers however.
It is possible that the quality has changed over the years ( deteriorated) as they are made in China, anything goes.
Glen
My chinese sprag is now 4 years old and still working well, as for the original engine sprockets, they are stamped not cast. The original sprockets are made from material with a soft core, I changed the material on the AN ones back in 2016 to a case hardening steel with a tougher core. Realistically I would not use the original engine sprocket, if yours has 'brinneling' then swap out next time your in the primary drive.
We have had chinese sprags that would not fit in one bike, but when I made it up on a crank they fitted fine.
We have had chinese sprags that would not fit in one bike, but when I made it up on a crank they fitted fine.
I had to dismantle the primary to change a gearbox leaking seal, and took the opportunity to install the DynoDave starter motor i have just purchased, the Chinese sprag had been working perfect for around 60 starts with the original Prestolite motor but when i took it out of the engine one of the bearing legs fall off from the cage... I change it for another new sprag as I thought it was not a good idea to re install back, what do you think?.
I have installed an Stieber DC-4127 (3C) - N original, will see if it gives a good work as the aliexpress did.
I have installed an Stieber DC-4127 (3C) - N original, will see if it gives a good work as the aliexpress did.
I have an Alton with a Sprage in it. What lubricant should one use on the bearings in the sprage that do the one way engagement. I have heard to fill 1/3 of the cavity with grease and also heard to spray dry lube into it. Would appreciate to hear what you think.
If your primary is by Chain, you don't need to do anything as it will lubricate with the primary chain movement.
If is belt drive.... I don't really know how can a sprage work without lubricant...
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If the sprag 'flips' then it won't grip at all.
If it actually breaks as mine did with an almighty crunch, it locked the motor drive to the crank! I managed to free it by putting the bike in gear and then sharply pushing it backwards several times until the sprag eventually freed off and I could then kickstart bike.
Unaware of the level of destruction I rode home.
Stripping the primary, this was what I found...
This 14 sprag unit was the old 'split-cage' type. Thankfully the sprags are no longer made with the slots cut into the cage.
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Just to update this thread, the Chicom sprag is now $65.
robs ss
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I hadn't thought about that.
Does anyone know what the recommended maintenance for a dry (belt) sprag is? Mine is cNw, but doesn't get much work. @L.A.B. - Les was your failed one above in oil or not?
If no-one springs to the rescue I guess I'll have to chase it down.
Cheers
robs ss
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Okay.... sprags in dry primary cases...
I found a US company that makes sprag clutches (GMN Bearings) who have on their website:
I bought a 45 gram tube of the top one from an online BMX shop in Australia.
Strangely, I contacted Shell, who replied that they don't have a product for that application but I could try their Gudus S3 wheel bearing grease - It has EP additives, so off the list.
Cheers
I found a US company that makes sprag clutches (GMN Bearings) who have on their website:
I bought a 45 gram tube of the top one from an online BMX shop in Australia.
Strangely, I contacted Shell, who replied that they don't have a product for that application but I could try their Gudus S3 wheel bearing grease - It has EP additives, so off the list.
Cheers
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